1. Field of the Invention
This invention relates to fuzes for ammunition for normally maintaining the ammunition in a safe configuration and for shifting to an armed configuration upon the concurrence of setback and centrifugal forces.
2. Prior Art
Fuzes of this general type are well known in the prior art, and are shown, for example, in U.S. Pat. No. 3,397,640, issued to Ziemba et al on Aug. 20, 1968; U.S. Pat. No. 3,595,169, issued to Ziemba on July 27, 1971; U.S. Pat. No. 3,608,494, issued to Ziemba on Sept. 28, 1971; U.S. Pat. No. 3,489,089, issued to Kaiser et al on Jan. 13, 1970; U.S. Pat. No. 3,302,572, issued to Lindberg et al on Feb. 7, 1967; U.S. Pat No. 3,479,955, issued to Birkigt on Nov. 25, 1969; U.S. Pat. No. 3,516,359, issued to Weber et al on June 23, 1970; U.S. Pat. No. 3,616,757, issued to Berger on Nov. 2, 1971; U.S. Pat. No. 3,585,935, issued to Birkigt on June 22, 1971; U.S. Pat. No. 3,994,230, issued to Kahn on Nov. 30, 1976; U.S. Pat. No. 3,995,557, issued to Engel et al on Dec. 7, 1976; the USAR A-20, A- 23 and A-25 projectile fuzes, and the US XM722 and XM714 projectile fuzes. These fuzes employ various combinations of ball rotors, unwinding ribbons and/or dash pots. However, none provides a system which permits the rotor to arm a consistent and predetermined interval of time after both spin and setback forces are present simultaneously. The dash-pot design of the XM714 and XM722 particularly has problems with (1) aging seals, (2) air leaks, (3) piston surge, (4) ambient temperature and pressure sensitivity, (5) spin rate sensitivity and (6) parts lubricity.